aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char/tpm/tpm_ppi.c
blob: 61dcc8011ec711246727ce5c2750277f33c219f4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
#include <linux/acpi.h>
#include "tpm.h"

#define TPM_PPI_REVISION_ID	1
#define TPM_PPI_FN_VERSION	1
#define TPM_PPI_FN_SUBREQ	2
#define TPM_PPI_FN_GETREQ	3
#define TPM_PPI_FN_GETACT	4
#define TPM_PPI_FN_GETRSP	5
#define TPM_PPI_FN_SUBREQ2	7
#define TPM_PPI_FN_GETOPR	8
#define PPI_TPM_REQ_MAX		22
#define PPI_VS_REQ_START	128
#define PPI_VS_REQ_END		255
#define PPI_VERSION_LEN		3

static const u8 tpm_ppi_uuid[] = {
	0xA6, 0xFA, 0xDD, 0x3D,
	0x1B, 0x36,
	0xB4, 0x4E,
	0xA4, 0x24,
	0x8D, 0x10, 0x08, 0x9D, 0x16, 0x53
};

static char tpm_ppi_version[PPI_VERSION_LEN + 1];
static acpi_handle tpm_ppi_handle;

static acpi_status ppi_callback(acpi_handle handle, u32 level, void *context,
				void **return_value)
{
	union acpi_object *obj;

	if (!acpi_check_dsm(handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
			    1 << TPM_PPI_FN_VERSION))
		return AE_OK;

	/* Cache version string */
	obj = acpi_evaluate_dsm_typed(handle, tpm_ppi_uuid,
				      TPM_PPI_REVISION_ID, TPM_PPI_FN_VERSION,
				      NULL, ACPI_TYPE_STRING);
	if (obj) {
		strlcpy(tpm_ppi_version, obj->string.pointer,
			PPI_VERSION_LEN + 1);
		ACPI_FREE(obj);
	}

	*return_value = handle;

	return AE_CTRL_TERMINATE;
}

static inline union acpi_object *
tpm_eval_dsm(int func, acpi_object_type type, union acpi_object *argv4)
{
	BUG_ON(!tpm_ppi_handle);
	return acpi_evaluate_dsm_typed(tpm_ppi_handle, tpm_ppi_uuid,
				       TPM_PPI_REVISION_ID, func, argv4, type);
}

static ssize_t tpm_show_ppi_version(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	return scnprintf(buf, PAGE_SIZE, "%s\n", tpm_ppi_version);
}

static ssize_t tpm_show_ppi_request(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	ssize_t size = -EINVAL;
	union acpi_object *obj;

	obj = tpm_eval_dsm(TPM_PPI_FN_GETREQ, ACPI_TYPE_PACKAGE, NULL);
	if (!obj)
		return -ENXIO;

	/*
	 * output.pointer should be of package type, including two integers.
	 * The first is function return code, 0 means success and 1 means
	 * error. The second is pending TPM operation requested by the OS, 0
	 * means none and >0 means operation value.
	 */
	if (obj->package.count == 2 &&
	    obj->package.elements[0].type == ACPI_TYPE_INTEGER &&
	    obj->package.elements[1].type == ACPI_TYPE_INTEGER) {
		if (obj->package.elements[0].integer.value)
			size = -EFAULT;
		else
			size = scnprintf(buf, PAGE_SIZE, "%llu\n",
				 obj->package.elements[1].integer.value);
	}

	ACPI_FREE(obj);

	return size;
}

static ssize_t tpm_store_ppi_request(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	u32 req;
	u64 ret;
	int func = TPM_PPI_FN_SUBREQ;
	union acpi_object *obj, tmp;
	union acpi_object argv4 = ACPI_INIT_DSM_ARGV4(1, &tmp);

	/*
	 * the function to submit TPM operation request to pre-os environment
	 * is updated with function index from SUBREQ to SUBREQ2 since PPI
	 * version 1.1
	 */
	if (acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
			   1 << TPM_PPI_FN_SUBREQ2))
		func = TPM_PPI_FN_SUBREQ2;

	/*
	 * PPI spec defines params[3].type as ACPI_TYPE_PACKAGE. Some BIOS
	 * accept buffer/string/integer type, but some BIOS accept buffer/
	 * string/package type. For PPI version 1.0 and 1.1, use buffer type
	 * for compatibility, and use package type since 1.2 according to spec.
	 */
	if (strcmp(tpm_ppi_version, "1.2") < 0) {
		if (sscanf(buf, "%d", &req) != 1)
			return -EINVAL;
		argv4.type = ACPI_TYPE_BUFFER;
		argv4.buffer.length = sizeof(req);
		argv4.buffer.pointer = (u8 *)&req;
	} else {
		tmp.type = ACPI_TYPE_INTEGER;
		if (sscanf(buf, "%llu", &tmp.integer.value) != 1)
			return -EINVAL;
	}

	obj = tpm_eval_dsm(func, ACPI_TYPE_INTEGER, &argv4);
	if (!obj) {
		return -ENXIO;
	} else {
		ret = obj->integer.value;
		ACPI_FREE(obj);
	}

	if (ret == 0)
		return (acpi_status)count;

	return (ret == 1) ? -EPERM : -EFAULT;
}

static ssize_t tpm_show_ppi_transition_action(struct device *dev,
					      struct device_attribute *attr,
					      char *buf)
{
	u32 ret;
	acpi_status status;
	union acpi_object *obj = NULL;
	union acpi_object tmp = {
		.buffer.type = ACPI_TYPE_BUFFER,
		.buffer.length = 0,
		.buffer.pointer = NULL
	};

	static char *info[] = {
		"None",
		"Shutdown",
		"Reboot",
		"OS Vendor-specific",
		"Error",
	};

	/*
	 * PPI spec defines params[3].type as empty package, but some platforms
	 * (e.g. Capella with PPI 1.0) need integer/string/buffer type, so for
	 * compatibility, define params[3].type as buffer, if PPI version < 1.2
	 */
	if (strcmp(tpm_ppi_version, "1.2") < 0)
		obj = &tmp;
	obj = tpm_eval_dsm(TPM_PPI_FN_GETACT, ACPI_TYPE_INTEGER, obj);
	if (!obj) {
		return -ENXIO;
	} else {
		ret = obj->integer.value;
		ACPI_FREE(obj);
	}

	if (ret < ARRAY_SIZE(info) - 1)
		status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret, info[ret]);
	else
		status = scnprintf(buf, PAGE_SIZE, "%d: %s\n", ret,
				   info[ARRAY_SIZE(info)-1]);
	return status;
}

static ssize_t tpm_show_ppi_response(struct device *dev,
				     struct device_attribute *attr,
				     char *buf)
{
	acpi_status status = -EINVAL;
	union acpi_object *obj, *ret_obj;
	u64 req, res;

	obj = tpm_eval_dsm(TPM_PPI_FN_GETRSP, ACPI_TYPE_PACKAGE, NULL);
	if (!obj)
		return -ENXIO;

	/*
	 * parameter output.pointer should be of package type, including
	 * 3 integers. The first means function return code, the second means
	 * most recent TPM operation request, and the last means response to
	 * the most recent TPM operation request. Only if the first is 0, and
	 * the second integer is not 0, the response makes sense.
	 */
	ret_obj = obj->package.elements;
	if (obj->package.count < 3 ||
	    ret_obj[0].type != ACPI_TYPE_INTEGER ||
	    ret_obj[1].type != ACPI_TYPE_INTEGER ||
	    ret_obj[2].type != ACPI_TYPE_INTEGER)
		goto cleanup;

	if (ret_obj[0].integer.value) {
		status = -EFAULT;
		goto cleanup;
	}

	req = ret_obj[1].integer.value;
	res = ret_obj[2].integer.value;
	if (req) {
		if (res == 0)
			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
					   "0: Success");
		else if (res == 0xFFFFFFF0)
			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
					   "0xFFFFFFF0: User Abort");
		else if (res == 0xFFFFFFF1)
			status = scnprintf(buf, PAGE_SIZE, "%llu %s\n", req,
					   "0xFFFFFFF1: BIOS Failure");
		else if (res >= 1 && res <= 0x00000FFF)
			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
					   req, res, "Corresponding TPM error");
		else
			status = scnprintf(buf, PAGE_SIZE, "%llu %llu: %s\n",
					   req, res, "Error");
	} else {
		status = scnprintf(buf, PAGE_SIZE, "%llu: %s\n",
				   req, "No Recent Request");
	}

cleanup:
	ACPI_FREE(obj);
	return status;
}

static ssize_t show_ppi_operations(char *buf, u32 start, u32 end)
{
	int i;
	u32 ret;
	char *str = buf;
	union acpi_object *obj, tmp;
	union acpi_object argv = ACPI_INIT_DSM_ARGV4(1, &tmp);

	static char *info[] = {
		"Not implemented",
		"BIOS only",
		"Blocked for OS by BIOS",
		"User required",
		"User not required",
	};

	if (!acpi_check_dsm(tpm_ppi_handle, tpm_ppi_uuid, TPM_PPI_REVISION_ID,
			    1 << TPM_PPI_FN_GETOPR))
		return -EPERM;

	tmp.integer.type = ACPI_TYPE_INTEGER;
	for (i = start; i <= end; i++) {
		tmp.integer.value = i;
		obj = tpm_eval_dsm(TPM_PPI_FN_GETOPR, ACPI_TYPE_INTEGER, &argv);
		if (!obj) {
			return -ENOMEM;
		} else {
			ret = obj->integer.value;
			ACPI_FREE(obj);
		}

		if (ret > 0 && ret < ARRAY_SIZE(info))
			str += scnprintf(str, PAGE_SIZE, "%d %d: %s\n",
					 i, ret, info[ret]);
	}

	return str - buf;
}

static ssize_t tpm_show_ppi_tcg_operations(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
{
	return show_ppi_operations(buf, 0, PPI_TPM_REQ_MAX);
}

static ssize_t tpm_show_ppi_vs_operations(struct device *dev,
					  struct device_attribute *attr,
					  char *buf)
{
	return show_ppi_operations(buf, PPI_VS_REQ_START, PPI_VS_REQ_END);
}

static DEVICE_ATTR(version, S_IRUGO, tpm_show_ppi_version, NULL);
static DEVICE_ATTR(request, S_IRUGO | S_IWUSR | S_IWGRP,
		   tpm_show_ppi_request, tpm_store_ppi_request);
static DEVICE_ATTR(transition_action, S_IRUGO,
		   tpm_show_ppi_transition_action, NULL);
static DEVICE_ATTR(response, S_IRUGO, tpm_show_ppi_response, NULL);
static DEVICE_ATTR(tcg_operations, S_IRUGO, tpm_show_ppi_tcg_operations, NULL);
static DEVICE_ATTR(vs_operations, S_IRUGO, tpm_show_ppi_vs_operations, NULL);

static struct attribute *ppi_attrs[] = {
	&dev_attr_version.attr,
	&dev_attr_request.attr,
	&dev_attr_transition_action.attr,
	&dev_attr_response.attr,
	&dev_attr_tcg_operations.attr,
	&dev_attr_vs_operations.attr, NULL,
};
static struct attribute_group ppi_attr_grp = {
	.name = "ppi",
	.attrs = ppi_attrs
};

int tpm_add_ppi(struct kobject *parent)
{
	/* Cache TPM ACPI handle and version string */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
			    ppi_callback, NULL, NULL, &tpm_ppi_handle);
	return tpm_ppi_handle ? sysfs_create_group(parent, &ppi_attr_grp) : 0;
}

void tpm_remove_ppi(struct kobject *parent)
{
	if (tpm_ppi_handle)
		sysfs_remove_group(parent, &ppi_attr_grp);
}